1989 chevy k-5 5.7 TBI on 1999 Chevrolet Silverado 1500

PLEASE HELP , 89 CHEVY K-1500 5.7 TBI RUNS ROUGH AT COLD START AFTER WARMS UP RUNS LIKE NEW DRIVE AROUND ABOUT 30 MINUTES GET HOT THEN SHUT OFF FOR ABOUT 30 MINUTES COME BACK AND TRY TO START SOUNDS FLOODED AND WONT START IF YOU GET IT STARTED RUNS EXTREMLY ROUGH AND YOU HAVE TO PLAY WITH GAS PETAL TO KEEP IT GOING FOR ABOUT 5 MIN. THEN STARTS TO SMOOTH OUT, I REPACED PLUGS ,WIRES,GAS FILTER,EGR, EGR SOLENOID,KNOCK SENSOR,FUEL PRESSURE REGULATOR CAN ANYONE HELP I HAVE TAKEN IT TO TWO SHOPS BUT THEY ARE OF NO HELP, ONCE AGAIN 1989 CHEVY K-1500 5.7 TBI